Electric current rectifier construction



March 20, 1934. E KERN 1,951,732

ELECTRIC CURRENT RECTIFIER CONSTRUCTION Filed Feb.r 2v. 1932 Patented Mar. 20, 1934 rr STATES ELECTRIC CURRENT RECTIFIER CNSTRUCTION Erwin Kern, Ennetbaden, Switzerland, assigner to Aktiengesellschaft Brown Boveri & Cie.,

Baden, Switzerland, a joint-stock company of Switzerland Application February 27, 1932, Serial No. 595,537 1n Germany February 24, 1931 3 Claims.

This invention relates to improvements in the construction of electric current rectiers of the metallic vapor arcing type and particularly to the construction of the portion of the rectifier 5 structure in which the vaporizable material is retained when in its liquid form.

The vapor density within an electric current rectier of the metallic vapor arcing type has a very great influence on the operation of such rectifier. The vapor density may rise to such values, during the operation of the rectifier, as to tend to cause backiiring and other disturbances therein with the result that such rectiiiers must be provided with elaborate means for condensing the vapor and thus reducing the vapor density. Numerous means have also been proposed to reduce the vapor density by preventing excessive vaporizaton which, in an electric current rectier of the character above indicated, is chiefly 2G due to the movement of the arc over the surface of a pool of vaporizable material. forming one electrode of the rectier. Various means have, therefore, been proposed in the form of inserts into the vaporizable material, to which points the arc may attach or in the form of floats which limit the surface area of the vaporizable material exposed to the action of the arc.

When a iioat was used, an annular space was heretofore allowed to remain betweenthe edge 39 of the float and the surface of the member formn ing the side wall of the vaporizable material retainer with the resulting danger that the arc might attach itself to the surface of the material exposed between the float and the side wall and from such surface might move to the float or side wall itself with destructive consequences. Means such as covers for the annular space or insulating shields arranged within the space have been proposed to prevent attachment and movement of the arc over the surface of the material within the annual spacer or on the inner surface of the wall enclosing the vaporizable material.

All of the above constructions, however, have the disadvantage that the arc may attach at the line of contact between the vaporizable material and the inserts or fioats, whether made of metal or insulating material, and may move to the insert or oat with resulting damage or destruction of the same.

It is therefore an object of the present invention to provide a construction of the portion of an electric current rectier of the metallic vapor arcing type which retains the vaporizable ma terial in its liquid form in which construction (Cl. Z-27.5)

movement of the arc over the surface of the vaporizable material is restricted.

Another object of the invention is to provide a construction of the portion of an electric current rectifier' of the metallic vapor arcing type which retains the vaporizable material in its liquid form in which construction the arc is prevented from attaching to portions of the structure other than the vaporizable material.

Another object of the invention is to provide a construction of the portion of an electric current rectier of the metallic vapor arcing type which retains the vaporizable material in its liquid form in which construction the arc is prevented from attaching at the line of contact of the Vaporizable material with other portions of the structure.

Objects and advantages other than those above set forth will be apparent from the following description when read in connection with the accompanying drawing which is a vertical cross sectional view of a portion of an electric current rectier of the metallic vapor arcing type embodying the present invention.

Referring more particularly to the drawing by characters of reference, the reference numeral l designates a portion of the substantially conical bottom of a tank within which an arc is maintained through a metallic vapor to produce an electric current rectifying action. The bottom of the tank 1 is formed with an aperture therethrough which is closed by a member 2 forming a retainer or well for a pool of vaporizable material 3, such as mercury, forming the cathode of the rectifier. The cathode well 2 is attached to the bottom of the tank 1 by means of studs 4 which serve to compress a gasket 6 of insulating material by which the joint between the weil 2 and the bottom of the tank is sealed. The well is preferably made double-walled by means of a jacket 5 to permit the circulation between the walls thereof of a cooling medium supplied from a suitable source (not shown) through the pipe 7 and discharged therefrom by a pipe connection 3 into the space between the double-walls of the rectifier tank l.

A member 11, formed with a cylindrical portion for attachment on the cathode well 2 and a smaller cylindrical portion extending downwardly into the well, the two` cylindrical portions being joined by a conical portion having apertures 12 therethrough, forms a guide for the movement of a substantially annular member 13 floating in the mercury 3. The float 13 is provided with an upwardly and inwardly extending flange 14 which extends about the smaller cylindrical portion of the guide 11 thus guiding the vertical movement of the oat and determining the position of the float relative to the vertical axis of the cathode well 2. A iiange 15 is formed to extend inwardly from the float member from such a portion thereof as to be above and out of contact with the surface of the mercury 3. The Width of the flange l5 is such that it is impossible for an arc to attach to the mercury at the line of contact thereof with the float.

A portion of the material 3 which is vaporized by the arc and condensed by contact with the cooled walls of the rectier tank flows over the bottom thereof into a collecting channel formed by a collar 17 extending upwardly from the bottom 1 about the aperture therethrough. A plate 18 is secured on the collar and extends in spaced relation over the collecting channel and over a portion of the tank bottom to protect the mercury therein from the action of the arc flowing close by. The bottom of the collecting channel is pierced by holes 19 registering with the holes 12 in the guide to permit the return of the condensed mercury to the cathode without contact with the arc. Flow of mercury over the guide and discharge therefrom on the ange 15 is prevented by a flange-like member 21 extending about the guide adjacent to the apertures 12 therethrough thus forming a channel which guides the mercury through the apertures 12.

Both the guide 11 and the floatJ 13 may be either of metal or of insulating material. If the guide and the float are made of metal, a magnetic eld is formed which extends largely parallel with the surface of the mercury 3 and thus aids in preventing movement of the arc over the surface of the mercury beyond the area defined by the inner edge of the flange 15. Attachment of the arc at the points of contact of the float with the mercury is thus positively prevented. The construction of a cathode container or well according to the present invention permits the insulating and sealing gasket 6 to be made much smaller than heretofore and permits such gasket to be located at a point remote from the thermal stresses set up by the arc.

Although but one embodiment of the invention has been illustrated and described, it will be apparent to those skilled in the art that various changes and modications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

It is claimed and desired to secure by Letters Patent:

1. In an electric current rectier, a tank having an aperture through the bottom thereof, a retainer arranged to close the aperture, a Vaporizable liquid within said retainer, a substantially annular float carried by said liquid, said float having a flange extending inwardly into the aperture therethrough and above the surface of said liquid to define the free area of the latter, and means for guiding the movement of said float in response to variations in the level of said liquid.

2. In an electric current rectifier, a tank having an aperture through the bottom thereof, a retainer arranged to close the aperture, a liquid retained within said retainer and vaporizable upon the attachment of an arc thereto, a float carried by said liquid, means for guiding the movement of said float upon variations in the level of said liquid, said float and said guiding means cooperating to restrict the area of said liquid to the portion thereof dened by said float, and a collecting channel for said liquid condensed from the vapor' thereof in said tank adjacent the aperture therethrough, said guide means and said channel having apertures to return said liquid to said retainer without coming into contact with an arc attaching to said liquid.

3. In an electric current rectier of the vapor arcing type, a cooled tank having an aperture through the bottom thereof, a cup-shaped closure for the aperture in said tank, a vaporizable liquid retained within said closure, a float of insulating material carried by said liquid and having an aperture therethrough, said oat having an inwardly extending iiange above the level of said liquid and defining the aperture through said float, and means connected with said closure for guiding the movement of said float upon variation in the level of said liquid, said oat and said guiding means cooperating to restrict the exposed area of said liquid to only the free area of the aperture in said float and cooperating to provide a path for the return of condensed liquid without coming into contact with an arc attached to said liquid.

ERVVIN KERN. 

